N-224. Diversity of Chloroflexus-Like Organisms in an Iron-Depositing Hot Spring in Yellowstone National Park

M. N. Parenteau1, S. M. Boomer2, K. L. Noll2, B. E. Dutton2, S. L. Cady3, L. L. Jahnke1, B. K. Pierson4;
1NASA Ames Res. Ctr., Moffett Field, CA, 2Western Oregon Univ., Monmouth, OR, 3Portland State Univ., Portland, OR, 4Univ. of Puget Sound, Tacoma, WA.

We have been investigating the possibility of Fe2+ oxidation by Chloroflexus sp. in the Synechococcus-Chloroflexus mats at Chocolate Pots hot springs in Yellowstone National Park. In vivo pigment analyses detected bacteriochlorophylls a and c, confirming the presence of Chloroflexus. However, a survey of the lipid biomarkers revealed diverse wax esters, suggesting that other filamentous anoxygenic phototrophs (FAPs) were present. We performed a molecular characterization of the FAPs at Chocolate Pots, and hypothesized that this unique, slightly acidic, metal-rich environment may contain a distinct cluster within the FAP lineage. We prepared 16S rRNA libraries from the Synechococcus-Chloroflexus mat by using a combination of FAP-specific primers and general bacterial primers. We analyzed 48 FAP-like clones and found that 90% were most similar to the Roseiflexus sp. RS-1 genome, the organism that typifies the “red” lineage within the family Chloroflexaceae. Phylogenies constructed by using FAP-like clones revealed a site-specific subcluster within the “red” lineage. There was also a well-supported distinct cluster not similar to any known cultured “red” or “green” representatives. This survey contributes to the efforts of Boomer and colleagues in determining the Park-wide distribution and diversity of novel FAPs in the NSF Red Layer Microbial Observatory.